#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int N;
  cin>>N;
  vector<int> S(N+1);
  for(int i=1;i<=N;i++){
      cin>>S[i];
      if(abs(S[i]-S[i-1]) != 1){
          cout<<'F'<<endl;
          return 0;
      }
  }
  cout<<'T'<<endl;
}